Original paper

Barrier spit accretion model of Southern Sylt, German North Sea:Insights from ground-penetrating radar surveys and sedimentological data

Tillmann, Tanja; Wunderlich, Jürgen


A sedimentary model of barrier spit accretion based on geophysical and sedimentological data is presented. The main focus lies on the reconstruction of the geological development of the southern barrier spit of Sylt (North Sea/German Bight) during the Holocene. The stratigraphy, sedimentary structure, and architecture of this island spit system were investigated through an integrated approach using high-resolution ground-penetrating radar (GPR) and sedimentological analyses of shallow sediment cores drilled at selected sites along the radar profiles. Based on detailed radar- and sediment-facies analysis the model of the southern barrier spit describes the major episodes of spit evolution. It shows that southerly barrier spit accretion into the tidal inlet was interrupted by erosional events during severe storm surges. Between distinct storm surges longshore currents along the west coast of Sylt provided the southern spit-end with sediment. Spit growth during this phase depended on the interval of storm surges. Annual winter storms set off erosional overwash processes which formed elongate washover channels. During stable stages of sea level horizontal beach deposits and foredunes were accumulated, the latter forming the present dune area of the southern island spit of Sylt.


barrier islandbarrier spit accretiongerman bightground-penetrating radarnorth seasyltwashover